Triple emulsion cosmetic/dermatological product

ABSTRACT

The invention concerns a cosmetic/dermatological product comprising a triple water-in-oil-in-water (W/O/W) emulsion including an outer aqueous phase, an intermediate oily phase and an inner aqueous phase. Said inner aqueous phase and/or said oily phase contains at least an active principle promoting lipolysis and/or an active principle inhibiting lipogenesis and said intermediate oily phase consists of oleosomes. The invention also concerns a method for obtaining as well as a method for using such a cosmetic/dermatological product.

The present invention concerns a cosmetic or dermatological product toprevent and/or act on cellulite. The invention also concerns a processof manufacturing this product as well as a use of the latter byapplication to the skin.

A large number of cosmetic products having a slimming action areavailable on the market. Some of these products are in the form of anemulsion.

In the state of the art, a type of emulsion, called triple or multipleemulsion, is also known. A triple emulsion comprises three phases: aninner phase dispersed in the form of droplets in an intermediate phase,itself dispersed in the form of droplets in an outer phase. It is knownin particular how to make triple water-in-oil-in-water emulsions(conventionally noted W/O/W) by preparing in a first step a simplewater-in-oil emulsion (W/O) and by dispersing, in a second step, thisemulsion in water.

A method for obtaining a triple emulsion W/O/W in a single step has beenproposed in the document WO-A-98 55 088. According to this method, acombination of hydrophilic and hydrophobic surfactants is dissolved inan oily phase, the oily phase is subsequently added to into the aqueousphase, then dispersed in a single step by agitation. The formation ofoil droplets surrounded by a layer of liquid crystals is observed. Thesedroplets, also called oleosomes, contain an emulsion W/O. In the end, atriple emulsion W/O/W is obtained. In this type of triple emulsion, itwill be noted that the composition of the outer aqueous phase isidentical to that of the inner aqueous phase.

The present invention results from the discovery according to which atriple emulsion obtained by said process in one step and comprising inits aqueous phase and/or in its oily phase slimming active principlesis, in a surprising way, substantially more efficient than aconventional simple emulsion.

More precisely, the present invention is defined by a cosmetic productcomprising a triple water-in-oil-in-water emulsion (W/O/W) comprising anouter aqueous phase, an intermediate oily phase and an inner aqueousphase, said inner aqueous phase and/or said oily phase containing atleast one active principle promoting lipolysis and/or inhibitinglipogenesis and said intermediate oily phase being constituted byoleosomes.

The invention is also defined by a dermatological product comprising atriple water-in-oil-in-water emulsion (W/O/W) comprising an outeraqueous phase, an intermediate oily phase and an inner aqueous phase,said inner aqueous phase and/or at least said oily phase containing atleast one active principle promoting lipolysis and/or inhibitinglipogenesis and said intermediate oily phase being constituted byoleosomes.

The invention further concerns a process of manufacturing said cosmeticor dermatological product. This process comprises a first step ofpreparing, in a separate manner, two phases, aqueous and oily, said oilyphase containing hydrophilic and hydrophobic surfactants and saidaqueous phase and/or the oily phase containing at least one slimmingactive principle, a second step of incorporating the oily phase to theaqueous phase and a third step of agitating the mixture thus formeduntil obtaining a triple emulsion W/O/W.

Finally, the invention concerns a use of said cosmetic product, so as toreduce the weight excess of a human body.

The preparation of the cosmetic/dermatological product according to theinvention has been carried out under the following conditions.

For the preparation of the intermediate oily phase of the tripleemulsion, a mixture of a highly polar oil (PPG-15-stearyl ether) withanother oil of any type has been advantageously used. The addition ofthe components has been systematically made in the direction oil towardswater. The dispersion has been made by agitation.

According to an experimental embodiment, the triple emulsion W/O/W isobtained by preparing separately each of the oily and aqueous phases.

The composition of the oily phase is as follows:

-   -   2% steareth-21    -   3% steareth-2    -   0.5% PEG-30 Dipolyhydroxystearate (PEG-Polyethyleneglycol)    -   5% PPG-15 stearyl ether (PPG =polypropyleneglycol)    -   2% jojoba oil    -   1% cetylic alcohol    -   1.5% stearic palmitic acid    -   1% dimethicone    -   1%        phenoxyethanol+methylparaben+ethylparaben+isobutylparaben+butylparaben+propylparaben        (paraben=parahydroxybenzoate)    -   2% sweet almond oil

On the other hand, the composition of the aqueous phase is as follows:

-   -   QSP demineralized water    -   Colorings    -   4% propyleneglycol    -   0.2% caffeine anhydrous powder    -   1% Phyco R75 (algae extract (laminaria))    -   5% Rhodofiltrat Palmaria HG (alga)    -   1.3% acrylamide/sodium        acryloyldimethyltaurate+isohexadecane+polysorbate 80 copolymer

Each of the two phases is then heated to 80° C.

The aqueous phase is dispersed under high agitation (3000 tr/min during5 min), then the oily phase is added to the aqueous phase under vacuum(−0.3 Bar) and under high agitation (60 tr/min and counter agitation 180tr/min).

The agitation is maintained for 15 min, then the mixture is left to cooldown to a temperature of about 53-55° C. Once this temperature isreached, 0.1% extract of Ondontella Aurita, perfume, and Thiethanolamineare added to the mixture thus obtained. Agitation is carried out againduring 15 minutes before letting cool to obtain a temperature of 25-30°C.

The cosmetic composition obtained comprises three phases: an inneraqueous phase, an intermediate oily phase and an outer aqueous phase. Ashas been said, the inner and outer aqueous phases have the samecomposition. The hydrophilic active principles incorporated within thestarting inner aqueous phase (caffeine, Phyco R75, RhodofiltratPalmaria), are found after formation of the emulsion within the dropletsof the inner aqueous phase as well as in the outer aqueous phase. Thelipophilic active principles (here, the extract of Odontella Aurita)added to the mixture are found, for their part, in the intermediate oilyphase.

The intermediate oily phase is in the form of oily droplets surroundedby liquid crystal lamellae, in other words, oleosomes.

According to a preferred embodiment, the active principles used arealgae extracts. However, other active principles having slimmingproperties such as from xanthic bases such as caffeine can beenvisioned, in some cases, in combination with said algae extracts.Thus, in the example above, the active principles are: Phyco R75,Rhodofiltrat Palmaria HG, caffeine and an extract of Odontella Aurita.

As will be seen below, it has been shown through tests that the actionof these active principles is substantially more pronounced in the caseof a triple emulsion than in the case of a simple emulsion.

The cosmetic/dermatological product according to the invention isapplied onto the skin of the part of the body to be treated. The actionof said product is attributed to the following mechanism. The dropletscomposing the intermediate oily phase of the triple emulsion oroleosomes migrate in the direction of the adipocytes located in thehypodermis. These oleosomes have an average size about equal to 15 μm.Having come into contact with the adipocytes, the oleosomes coalescewith the adipocytes and release within them the active principles thatthey contain.

The W/O/W emulsion obtained by the process in a single step makes itpossible to reach the hypodermis more easily than a simple emulsion oreven than a normal triple emulsion and enables a targeted release of theactive principles.

Depending on the type of active principle contained in the aqueous phaseand/or the oily phase, the action on the adipocytes will not be thesame. Some active principles degrade the fat present in the adipocytes,this is the phenomenon called lipolysis. Others act on the adipocytes bypreventing the formation of fat (triglycerides) within the adipocytes,this is the phenomenon called inhibition of the lipogenesis. Dependingon the case, a reduction of cellulite or a prevention of its worseningis obtained.

Among the active principles promoting lipolysis, caffeine and: PhycoR75, Rhodofiltrat Palmaria HG, will be preferentially used. Among theactive principles inhibiting lipogenesis, an extract of Odontella Auritawill be preferentially used.

A series of tests has made it possible to show the increased efficacy ofthe triple emulsion used in the cosmetic/dermatological productaccording to the invention, first with respect to a simple tripleemulsion, hereinafter called normal emulsion, but also with respect to aconventional triple emulsion, hereinafter called placebo 2.

The tests were performed on two groups each made up of twenty volunteersand the results were obtained by measuring the perimeter of the ankles,that of the thighs, as well as the thickness of the hypodermis byultrasound.

The first consisted in comparing a simple emulsion containing activeprinciples (so-called normal emulsion) with a placebo simple emulsion(placebo 1).

The second test consisted in comparing a zone treated by a placebotriple emulsion (placebo 2) to a non-treated zone.

And the third test consisted in comparing a zone treated with the tripleemulsion according to the invention with a non-treated zone.

The objective of these tests is to evaluate the efficacy of the tripleemulsion according to the invention, as compared to a simple emulsioncontaining the same active principles, and as compared to a conventionaltriple emulsion.

For each of these tests, a test is performed and the values obtainedduring these tests are compared to each other.

The test used is the test t of Student on matched values. The principleof the test consists in setting a null hypothesis (H0) of an absence ofany difference between the average effects of the two treatments (d=0)and an alternative hypothesis HI (the research hypothesis) of adifference between the two treatments d<>0). The probability p ofobserving a discrepancy between the two treatments at least as large asthat which was observed if the null hypothesis is true is thendetermined.

If p <5%, the null hypothesis is rejected. The alternative hypothesis H1of a significant difference between the two treatments is then accepted.

If p >5%, H0 is accepted. The data did not make it possible to show asignificant difference between the two treatments.

In the case of non-normality of the differences, a Wilcoxon test isperformed.

The principle of the test being defined, measurements of the thicknessof the adipose tissue are performed directly on the ultrasound negativesin the area of the front, lateral and back faces of the thighs. Thethicknesses are given in millimeters.

The first test consisted in comparing the averages and the standarddeviations with respect to the averages (SDA) obtained on the average ofthree zones of the thighs (front, lateral, and back faces of the thighs)after 56 days of application twice daily of, on the one hand, a normalemulsion, and on the other hand, a placebo 1 (Table 1).

The results are as follows: TABLE 1 Normal emulsion Placebo 1 J0 J56 J0J56 Average 14.2 14.0 14.0 13.9 SDA 0.6 0.6 0.6 0.7 Δ(J56-J0) −0.1 ± 0.3−0.1 ± 0.4 Δ%(J56-J0) −1% −1% Δ Emulsion/Placebo 0.0 ± 0.4 p = 0.942 Δ%Emulsion/Placebo 0%

As indicated by the Student test, no significant difference is observedbetween the thigh treated by the normal emulsion and the thigh treatedby the placebo 1.

The second test consisted in evaluating a placebo 2 alone, so as toshow, on the one hand, the average values of the thickness of thehypodermis of the volunteers using the product during the test (Table2), and on the other hand, the average variations in the thickness ofthe hypodermis of the volunteers using the placebo 2 (Table 3).

Thus, the results obtained without the placebo (NTZ) and with theplacebo (TZ) are compared after 28 and 56 days.

The results are as follows: TABLE 2 Zone treated Zone not treated by theplacebo (TZ) by the placebo (NTZ) (in mm) (in mm) J0 J28 J56 J0 J28 J56Average 35.8 35.7 32.6 35.3 35.7 33.0 SDA 2.2 2.3 2.3 2.5 2.5 2.6

TABLE 3 Δ TZ/NTZ Δ% TZ/NTZ J28-J0 J56-J0 J28-J0 J56-J0 Average −0.5 −1.6−0.9 −2.7 SDA 0.8 1.3 2.2 4.1 Student p 0.501 0.224

It is observed that after 28 and 56 days of using placebo 2 twice daily,the thickness of the hypodermis is not reduced significantly for thetreated thigh, as compared to the non-treated thigh.

The third test consisted in comparing the variations of results obtainedbetween a zone treated by the multiple emulsion according to theinvention and a non-treated zone.

These results are summarized, on the one hand, in Table 4 giving averagevalues of the thickness of the hypodermis in the zone treated with thetriple emulsion, as compared to the non-treated zone at 28 and 56 days,and on the other hand, in Table 5 giving the average variations of thethickness of the hypodermis between the zone treated by the tripleemulsion and the non-treated zone. TABLE 4 Treated zone (TZ) Non-treatedzone (NTZ) (in mm) (in mm) J0 J28 J56 J0 J28 J56 Average 30.5 28.2 29.225.9 27.3 29.0 SDA 2.1 1.8 2.2 2.0 1.8 2.1

TABLE 5 Δ treated zone/ Δ% treated zone/ non-treated zone non-treatedzone (in mm) (in %) J28-J0 J56-J0 J28-J0 J56-J0 Average −2.6 −4.6 −6.8−10.8 (n = 20) SDA 1.2 1.1 4.0 4.4 p 0.043 <0.001

It is then observed that after 28 and 56 days of using twice daily thetriple emulsion according to the invention, the thickness of thehypodermis is reduced significantly on the treated thigh, as compared tothe non-treated thigh. This is confirmed by the Student test which givesat 56 days a significant variation p <0.001.

Thus, the experimental results show an efficacy of the triple emulsionaccording to the invention considerably superior to that of the simpleemulsion and considerably superior to that of a conventional tripleemulsion.

1. Cosmetic product comprising a triple water-in-oil-in-water emulsion(W/O/W) comprising an outer aqueous phase, an intermediate oily phaseand an inner aqueous phase, wherein said inner aqueous phase and/or saidoily phase contains at least one active principle promoting lipolysisand/or active pinciple inhibiting lipogenesis, said intermediate oilyphase being constituted by oleosomes.
 2. Cosmetic product according toclaim 1, wherein at least one active principle is constituted byextracts from algae.
 3. Cosmetic product according to claim 1, whereinat least one active principle is a xanthic base, in particular caffeine.4. Cosmetic product according to claim 1, wherein said intermediate oilyphase contains an extract of Odontella Aurita as active principleinhibiting lipogenesis.
 5. Dermatological product comprising a triplewater-in-oil-in-water emulsion (W/O/W) comprising an outer aqueousphase, an intermediate oily phase and an inner aqueous phase, wherein atleast said inner aqueous phase contains at least one active principlepromoting lipolysis and/or at least said intermediate oily phasecontains at least one active principle inhibiting lipogenesis, saidintermediate oily phase being consistuted by oleosomes. 6.Dermatological product according to claim 5, wherein at least one activeprinciple is constituted by algae extracts.
 7. Dermatological productaccording to claim 5, wherein at least one active principle is a xanthicbase, in particular caffeine.
 8. Dermatological product according toclaim 5, wherein said intermediate oily phase contains an extract ofOdontella Aurita as active principle inhibiting lipogenesis.
 9. Processof manufacturing the cosmetic product according to claim 1, comprising afirst step of preparing the two phases, aqueous and oily, separately,said oily phase containing hydrophilic and hydrophobic surfactants, saidaqueous phase and/or the oily phase containing at least one slimmingactive principle, a second step of incorporating the oily phase to theaqueous phase, and a third step of agitating the mixture thus formeduntil obtaining a triple emulsion W/O/W.
 10. Process of manufacturingthe dermatological product according to claim 5, comprising a first stepof preparing the two phases, aqueous and oily, separately, said oilyphase containing hydrophilic and hydrophobic surfactants, said aqueousphase containing at least one slimming principle, a second step ofincorporating the oily phase to the aqueous phase, and a third step ofagitating the mixture thus formed until obtaining a triple emulsionW/O/W.
 11. Process of using the cosmetic product according to claim 1comprising applying the product cutaneously on a human body so as toreduce a weight excess of the latter.
 12. Cosmetic product according toclaim 2, wherein at least one active principle is a xanthic base, inparticular caffeine.
 13. Cosmetic product according to claim 2, whereinsaid intermediate oily phase contains an extract of Odontella Aurita asactive principle inhibiting lipogenesis.
 14. Cosmetic product accordingto claim 3, wherein said intermediate oily phase contains an extract ofOdontella Aurita as active principle inhibiting lipogenesis. 15.Cosmetic product according to claim 12, wherein said intermediate oilyphase contains an extract of Odontella Aurita as active principleinhibiting lipogenesis.
 16. Dermatological product according to claim 6,wherein at least one active principle is a xanthic base, in particularcaffeine.
 17. Dermatological product according to claim 6, wherein saidintermediate oily phase contains an extract of Odontella Aurita asactive principle inhibiting lipogenesis.
 18. Dermatological productaccording to claim 7, wherein said intermediate oily phase contains anextract of Odontella Aurita as active principle inhibiting lipogenesis.19. Dermatological product according to claim 16, wherein saidintermediate oily phase contains an extract of Odontella Aurita asactive principle inhibiting lipogenesis.